Aluminum does not rust, it oxidises — and oxidised aluminum goes from bright to grey to chalky white, which reads as neglect on a tanker or a trailer even when the unit is mechanically sound. Ordinary soap will not touch it, because the problem is a layer of aluminum oxide bonded to the metal rather than dirt sitting on top of it.
Brightening removes that layer chemically. Polishing then works the exposed metal to a reflective finish. They are two different jobs and the second is optional.
The process
Assess the alloy and the finish
Mill-finish, polished and coated aluminum respond differently, and anodised aluminum must not be acid-brightened at all. Getting this wrong is permanent, so it is settled before anything is applied.
Brighten
A controlled acid application dissolves the oxide layer. Dwell time is short and monitored — an acid left too long etches the surface it was meant to restore, which is the most common way this service is done badly.
Neutralise and rinse
The acid is neutralised and thoroughly rinsed. Residual acid keeps working after the crew leaves and will bloom back through the finish within weeks.
Polish
Mechanical polishing in progressive stages where a mirror finish is wanted. This is labour, and it is priced accordingly — a full trailer polish is a substantially bigger job than brightening the same trailer.
Typical work
- Aluminum tanker barrels and crude trailers
- Trailer skirts, rails, cross-members and rear frames
- Polished fuel tanks, steps and toolboxes
- Aluminum and chrome wheels
- Bumpers, visors, air cleaners and stacks
- Dump bodies and grain trailers
Why containment applies here too
Brightening runoff is acidic and carries dissolved aluminum. It is not something to send down a storm inlet, and it is the runoff most likely to be noticed if it reaches surface water. The same containment and recovery process used for fleet work applies: sealed inlets, vacuum recovery, onboard tank, off-site disposal.